title: Comprehensive analysis of the origin of eukaryotic genomes.
abstract: There is currently no consensus on the evolutionary origin of eukaryotes. In the search of the ancestors of eukaryotes, we analyzed the phylogeny of 46 genomes, including those of 2 eukaryotes, 8 archaea, and 36 eubacteria. To avoid the effects of gene duplications, we used inparalog pairs of genes with orthologous relationships. First, we grouped these inparalogs into the functional categories of the nucleus, cytoplasm, and mitochondria. Next, we counted the sister groups of eukaryotes in prokaryotic phyla and plotted them on a standard phylogenetic tree. Finally, we used Pearson's chi-square test to estimate the origin of the genomes from specific prokaryotic ancestors. The results suggest the eukaryotic nuclear genome descends from an archaea that was neither euryarchaeota nor crenarchaeota and that the mitochondrial genome descends from alpha-proteobacteria. In contrast, genes related to the cytoplasm do not appear to originate from a specific group of prokaryotes.
authors.affiliation: Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, Waseda Research Park, Saitama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saruhashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hamada
authors.forename: Daisuke
authors.initials: D
authors.lastname: Miyata
authors.forename: Tokumasa
authors.initials: T
authors.lastname: Horiike
authors.forename: Takao
authors.initials: T
authors.lastname: Shinozawa
mesh_terms: D000818:Animals; D005057:Eukaryotic Cells / Q000145:classification / Q000378:metabolism / Q000502:physiology; D019143:Evolution, Molecular; D016678:Genome / Q000502:physiology; D006801:Humans; D010802:Phylogeny; D011387:Prokaryotic Cells / Q000378:metabolism